Endemic Burkitt's lymphoma (BL) is the most common childhood cancer in low-lying humid regions of Equatorial Africa. In Kenya, the cancer is endemic in Nyanza Province. Within Nyanza Province, we have identified high risk and low risk clusters of BL. Two known co-factors for BL have been identified: holoendemic malaria and EBV infection. Holoendemic malaria transmission occurs throughout Nyanza Province and infection with EBV is not geographically restricted. This suggests that other co-factors in addition to EBV and holoendemic malaria increase the risk for BL resulting in the high-risk clusters of BL. Several lines of evidence suggest that another potential cofactor is micronutrient deficiency such as selenium. Selenium deficiency is associated with several types of cancer and selenium supplementation is chemopreventative for reducing cancer risks. We hypothesize that selenium deficiency occurs in the high BL risk area compared to the low BL risk area and thus could be an additional co-factor increasing the risk for BL. Furthermore, we hypothesize that selenium deficiency results in increased EBV viral load. In this proposal we will test these hypotheses by completing the following aims: determine selenium levels in children living in regions with low and high risk for BL and determine if reduced selenium levels correlate with elevated EBV viral load in children. We will perform a cross-sectional analysis of children living within two high-BL risk regions and two low-BL risk regions we identified in Nyanza Province. This proposal builds on our ongoing research projects in Kenya and the long- standing collaboration between the two co-investigators, one at SUNY Upstate and one at the Kenya Medical Research Institute (KEMRI). As an outcome of the proposed investigations, we expect to determine how selenium deficiencies correlate with 2 known co-factors, EBV and malaria, in a cohort of children at risk for developing BL. This knowledge is critical to determining the etiology of BL and ultimately, to prevent BL. This research will be done primarily in Kisumu, Kenya at the Center for Vector Biology Research and Control, Kenya Medical Research Institute in collaboration with P. Odada Sumba, as an extension of NIH grant #R01CA102667. Public Health Relevance: Burkitt's lymphoma remains the most common childhood malignancy in Equatorial Africa. We are studying what causes this cancer and why it is so common in children. We are testing the hypothesis that essential micronutrients are deficient in children that are living in a region in Kenya where there is a high risk for getting Burkitt's lymphoma.